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Connective / Supporting tissues:

Connective / Supporting tissues Dr Pankaj Maheria 1 Dr Pankaj

Objective :

Objective At the end of this learning session you would be able to Enumerate the characteristics of connective tissue List the cells found in CT Describe the components of Areolar tissue as a Prototype CT Distinguish between Dense regular, Irregular CT Elastic CT Reticular CT Dr Pankaj 2

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A basic type of tissue of mesoderm origin which provides structural and metabolic support for other tissues and organs throughout the body. 3 Dr Pankaj

General function :

General function Support the organs and cells Act as medium for exchange of nutrients and wastes between the blood and tissues Protects against microorganisms Repair damaged tissue Storage Packing 4 Dr Pankaj

Components of support tissue:

Extracellular matrix :

Fibres of supporting tissue:

Two main type Collagen ( including reticulin which was formerly considered a separate fibre type) Elastin Dr Pankaj 10 Fibres of supporting tissue

Collagen :

Main fibre type found in most supporting tissue. Most abundant protein in the human body function : provision of tensile strength Classified by roman numerals on the basis of the chronology of their discovery. 27 different types Type I and IV are the most abundant. Dr Pankaj 11 Collagen

Collagen :

Do not branch Run in wavy course. White in color when fresh Each collagen fibres consist of small parallel fibrils. Each fibils consist of bundle of parallel microfibrils which show cross striations. Dr Pankaj 12 Collagen

Collagen :

Secreted into the extracellular matrix in form of tropocollagen Tropocollagen is about 260 nm long and 1.5 nm thick Three polypeptide chain called alpha units. Synthesized by fibrobalst When boil become gelatin Dr Pankaj 13 Collagen

Elastic fibres:

Composed of protein called elastin Synthesized by fibroblast and smooth muscles cells (Blood vessles ) Fibres are single and not in bundle Branch and anastomose forming a network. Can be stretched Yellow in colour when fresh Found in ligament nuchae , ligament flava , large artery Dr Pankaj 16 Elastic fibres

Ground substance :

It is a transparent , homogeneous , viscous solution. Fills the space between cells and fibers. Acts as a molecular sieve facilitating diffusion of metabolites between blood and tissues. Dr Pankaj 17 Ground substance

Primitive mesenchymae:

Primitive mesenchymae Dr Pankaj 24 Embryological tissue from which all type of supporting tissue , including that of the skeleton are dervied Some cells remain in fully mature supporting tissue and act as stem cells Irregular, star or spindle in shape with delicated branching cytoplacmic processes Oval nuclei have isolated chromatin and visible nucleli Circulatory system of embyo is poorly developed untill a late stage and mesenchyme permits free diffusion of metabolites to and from developing tissue

Pericytes :

Pericytes Dr Pankaj 25 Derived from embryonic mesenchymal cells May returns to pluripotential role Charateristics of endothelial cells as well as smooth muscle cells because they contain actin , myosin and tropomyosin , suggesting that they have may function in contraction Smaller than fibroblast

Pericytes :

Pericytes Dr Pankaj 26 Location Mostly alone capillaries, yet they lie within their own basal lamina Function Modify capillary blood flow. During blood vessel formation and repair they may differentiated into smooth muscle cells as well as endothelial cells.

Fat cells (Adipocytes):

Fat cells ( Adipocytes ) Dr Pankaj 27 Aries from mesenchymal cells and perhaps from fibroblast Do not normally undergo cell division Increase in number in early neonatal life Store energy

Fat cells (Adipocytes):

Fat cells ( Adipocytes ) Dr Pankaj 28 Large cell 50 µm Each cell contains a large single lipid drop let which is dissolved by xylol during preparation of section, leaving a large empty space and athin rim of cytoplasm and peripheral nucleus- ring Supported by reticular fibrous

Fixed macrophages or histiocytes:

Derived from blood monocytes . Principal phagocytosing cells of connective tissue. Involved in phagocytosis – play a role in local defence of the body against bacterial invasion Form part of mononuclear phagocytic syatem Can be stain with vital dyes Fixed macrophages or histiocytes Dr Pankaj 30

Plasma cell:

Plasma cell Dr Pankaj 37 Cytoplasm is deeply basophilic because of an abudant of rER A prominent area adjacent to the nucleus appears pale and contain the golgi complex. Found more in lamina propria of GIT and respiratory tract. Russell’s body

Leucocytes :

Leucocytes Dr Pankaj 38 Nucleated WBC which migrate to connective tissue from blood vessels Found in large number during inflammatory condition. Perform phagocytosis or cell mediate immune response to specific foreign material or pathogens

Adipose tissue:

Adipose tissue Special type of connective tissue formed by aggregation of fat cells. 15- 20 % of body weight in men and 20-25% in women. Derived from primitive mesenchyme where they develop as lipoblast . Found subcutaneously in hypodermis throughout the body except over eyelid, penis , scrotum and lobule of auricle 44 Dr Pankaj

Adipose tissue:

Adipose tissue Function Reservoir of energy Shape to the body and keep organs in position Act as a shock absorber Thermal insulation to body 45 Dr Pankaj

Adipose tissue:

Adipose tissue Dr Pankaj 46 Big rounded cell Single – unilocular Flat peripheral nucleus Few Low Well develop Less vascular Widespread – found in adults Store house of energy Small polygonal cell Many – multilocular Spherical central nucleus Many with long cristae High Not well developed Highly vascular Limited – foetues and new borns Production of heat White adipocytes Brown adipocytes